1. Field of the Invention
The present invention generally relates to a drive force distribution control device for a four-wheel drive vehicle that can transmit a portion of a drive force headed toward a main drive wheel to a subordinate drive wheel in accordance with a control and can execute a distributed output of said portion of the drive force to a left subordinate drive wheel and a right subordinate drive wheel in accordance with a control.
2. Background Information
Japanese Laid-Open Patent Application Publication No. 07-017277 presents an example of a conventional drive force distribution control device for a four-wheel drive vehicle. The proposed technology compares a yaw rate corresponding to a turning behavior of the vehicle to a target yaw rate. If an over-steered state exists, then a drive force difference is imposed between turning-direction outside and turning-direction inside wheels such that an excessively large actual yaw rate is decreased and brought closer to a target yaw rate. If an under-steered state exists, then a drive force difference is imposed between turning-direction outside and turning-direction inside wheels such that an excessively small actual yaw rate is increased and brought closer to a target yaw rate.
With this conventional drive force distribution control, the actual yaw rate can be made to converge toward the target yaw rate using feedback control of the yaw rate even if the actual yaw rate has diverged from the target yaw rate.